Since Guitar Hero: World Tour features a full set of instruments that are nearly identical to Rock Band's, Activision decided that it was time to take the high road and make their PS3 hardware completely compatible with their competition. Great, right? Well it is, except for one minor catch: PS3 Guitar Hero drums are not working in Rock Band. Oh, and the Rock Band mic isn't working in Guitar Hero, either.Activision has yet to respond to the issues, but apparently their box lists using GH controllers outside of Activision properties as "expressly prohibited." Harmonix, who has traditionally supported cross-compatible instrumentation between the two franchises, has promised that "we are definitely looking into this. We'll keep you posted on updates as soon as more info is available." It's hard to believe that this lack of compatibility was anything but intentional on Activision's part since they've had access to Rock Band 2 for months...which is a particularly large problem since many gamers are plopping down almost $200 for the Guitar Hero World Tour software and instruments. Let's hope for some fancy software patches soon, though we're not holding our breath. [Kotaku and Joystiq]